Gaming machine having a distributed mode acoustic radiator

ABSTRACT

A transducer is affixed to the rear side of a display panel of a gaming machine so as to vibrate the glass and transmit sound to the player. In one embodiment, the transducer and panel form a distributed mode acoustic radiator, where sound is produced from the vibration of the panel due to resonant bending wave modes.

FIELD OF INVENTION

[0001] This invention relates to gaming machines and, in particular, to the audio portion of the gaming machine.

BACKGROUND

[0002] Prior art gaming machines, such as slot machines, frequently provide sound effects to add excitement to the play of a game. Such sound effects may include a melody while a game is being played and various sounds based upon the outcome of the game. One such slot machine displays either mechanical or video rotating reels with symbols on the reels' peripheries. The reels are randomly stopped using a pseudo-random number generator, and the combination of displayed symbols determines the award paid to the player. Such gaming machines incorporate a conventional speaker coupled to an audio amplifier. Stored digital sound effects are converted into analog signals, amplified, and applied to the speaker. The speaker is typically mounted at an opening in the slot machine, and a grill over the opening protects the delicate diaphragm of the speaker.

[0003] Such speakers, if mounted on the front of the slot machine, use some front surface area. It is desirable that this surface area used by the speaker(s) be kept to a minimum so that the front surface area can be used for displaying the game itself and to maximize the display glass that explains the pay table and advertises the game. Accordingly, the speakers are desirably small.

[0004] Speakers are also installed on the side wall of the machine, but this placement is not optimal for sound.

[0005] Accordingly, the sound produced by prior art gaming machines is of generally low quality.

SUMMARY

[0006] A transducer is affixed to the rear side of the display panel of a gaming machine so as to vibrate the glass and transmit sound to the player. The resiliency of the display panel may be optimized to better conduct the sound waves. In one embodiment, the display panel is formed of plastic instead of glass.

[0007] In one embodiment, the transducer and panel form a distributed mode acoustic radiator, where sound is produced from the vibration of the panel due to resonant bending wave modes.

[0008] Thus, the invention provides quality sound to the player without using any additional surface area for mounting a speaker. The sound quality may be improved by mounting a woofer in the gaming machine.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a perspective view of a conventional slot machine except that a vibration transducer is mounted on the back surface of a display panel.

[0010]FIG. 2 is a block diagram showing basic functional units within the gaming machine of FIG. 1.

[0011]FIG. 3 illustrates the back surface of a display panel having affixed to it a vibration transducer.

[0012]FIG. 4 is a cross-sectional view of one particular vibration transducer having its coil assembly rigidly affixed to the display panel.

[0013]FIG. 5 is a cross-sectional view of one particular vibration transducer having its magnet assembly rigidly affixed to the display panel.

DETAILED DESCRIPTION

[0014]FIG. 1 is a perspective view of a conventional video slot machine, although the invention may be used in slot machines having motor driven reels or in any other type of gaming machine. Machine 10 includes a display screen 12, which may be a CRT, an LCD, a thin film transistor (TFT) display, or any other type of screen. Alternatively, display screen 12 may simply be a transparent window through which motor driven reels are viewed.

[0015] Buttons 13 control the play of the game. Such buttons may include a bet button, spin reels button, cash out button, and any other buttons for controlling the game. If the game is a poker game, then the buttons include hold and deal buttons. If display screen 12 is a touch-screen, the player would touch areas on the screen to make a selection rather than press buttons.

[0016] A coin slot 14 receives coins, and an additional slot 15 receives bills, magnetic strip cards, smart cards, or paper tickets in order to generate credits in machine 10. A coin tray 16 receives the coins paid out by machine 10 in the event of a win or upon the player cashing out. Credits may also be paid via magnetic strip cards, smart cards or paper tickets.

[0017] A bottom display panel 18 typically has printed on it the name of the machine, and upper display panel 19 typically has printed on it a pay table identifying the amounts to be paid for various symbol combinations obtained during the game. Panels 18,19 may be glass or plastic.

[0018]FIG. 2 is a block diagram of various functional units within the gaming machine 10 of FIG. 1. A CPU 20 runs a gaming program stored in a program ROM 22. A player input block 24 includes any coin/credit detector and player selection buttons. A pay table ROM 26 detects the outcome of the game and identifies awards to be paid to the player. A payout device 28 pays out the award in the form of coins or credits. The payout may be in the form of credits on a smart card or magnetic strip card, a coded paper ticket, or in any other form. A display controller 30 receives commands from CPU 20 and generates signals for the display screen 12.

[0019]FIG. 2 also illustrates an audio amplifier 36, typically receiving signals from a sound card. The sound card receives digital signals from CPU 20, generates analog signals, and amplifies the analog signals. The output of the audio amplifier 36 is coupled to a transducer 38 affixed to the back of display panel 18 or 19. Transducer 38 can be a conventional audio frequency transducer that normally displaces a cone type diaphragm or may be the type that forms a distributed mode radiator, described below.

[0020]FIG. 3 illustrates the back surface of display panel 18 or 19 having a transducer 38 affixed to its back surface. Multiple transducers 38′ and 38″ may be used. Transducer 38, in response to the signal from amplifier 36, vibrates and imparts this vibration to the display panel 18,19 to produce sound. The player thus hears a sound emanating from the entire display panel 18,19. The sound has fairly uniform dispersion. The thickness, size, and material of display panel 18,19 are chosen for the best sound reproduction. The display panels 18,19 may be formed of glass or a polymer such as Perspex™ (an acrylic).

[0021]FIG. 4 is a cross-sectional view of one type of transducer 38 that may be used. Transducer 38 comprises a wire coil 42 fixed to a wall of a cylindrical coil former 44 by means of a rigid adhesive. The ends of the coil 42 are connected to amplifier 36 in FIG. 3. The coil former 44 is rigidly attached to the back surface of display panel 18 or 19 by an adhesive 40, which may be epoxy or other type of rigid adhesive. A bracket may also be used for simplifying manufacturing.

[0022] A magnet 46 is sandwiched between two metal plates 48 and 49 having high magnetic permeability, such as plates containing iron or nickel. The top plate 49 is resiliently secured to display panel 18 or 19 by means of a resilient suspension 52 such as rubber. In one embodiment, the resilient suspension is an O-ring affixed to both the display panel 18,19 and the top plate 49 by an adhesive. The magnetic assembly, comprising magnet 46 and plates 48 and 49, thus moves in a direction normal to the surface of display panel 18,19 due to the magnetic fields created by coil 42 when energized by a signal. The movement of the magnetic assembly causes a bending of the display panel 18,19 to set up resonating waves in the display panel 18,19. These waves displace air, causing sound to emanate from the display panel 18,19.

[0023] One transducer 38 that may be used is referred to as an inertial vibration transducer available from New Transducers Limited in the United Kingdom. Speakers using such transducers are sold by New Transducers Limited under the name NXT™. Such transducers are described in U.S. Pat. Nos. 6,192,136; 6,003,766; 6,342,831; and 6,332,029, all incorporated herein by reference, as well as in other patents.

[0024] Each display panel 18 and 19 may have its own separate transducer(s).

[0025] Mid and high audio frequencies are fairly directional. In the prior art, the mid and high audio frequencies output from the conventional speakers had to be directed toward the player's head by proper placement of the speakers in order to create the desirable audio effect. Using the display panel as a resonator causes the sound to emanate in all directions, so the player hears all the frequencies generated. Since the low audio frequencies are not efficiently generated using a resonant mode technique, a conventional woofer or sub-woofer may also be incorporated into machine 10 for low frequencies. Since low frequencies are not directional, the location of the woofer does not affect the sound quality.

[0026] In other embodiments, the magnetic assembly of the transducer 38 is rigidly affixed to the display panel 18,19, and the coil assembly is moveable with respect to the display panel 18,19. FIG. 5 illustrates such an embodiment where the magnetic assembly, comprising a magnet 60 and metal plates 62,63, are rigidly affixed to display panel 18,19. Coil 64 is encased in a rigid material and is resiliently held in place with respect to magnet 60 to allow coil 64 to move relative to magnet 60 when signals are applied to coil 64 by amplifier 36. The relative movements of the magnet 60 and coil 64 impart a vibration to display panel 18,19 to generate sound waves.

[0027] The signals used to energize the coil in transducer 38 move the magnet with respect to the coil on the order of 40 microns, barely bending the display panel 18,19, but creating a series of bending waves that travel in all directions. The amount of deflection and the excitation signal depend on the sound to be generated. The bending waves reflect from the edges of the panel 18,19 at different angles and at different speeds to create a chaotic mass of crossing bending waves that form the modes that produce the sound. Accordingly, the generation of sound is based upon resonances produced by the display panel 18,19. The resonant bending causes the display panel 18,19 to be displaced by greater than 40 microns, thus producing audible sound.

[0028] Using the language of U.S. Pat. No. 6,342,831, the panel 18,19 sustains and propagates the input vibrational energy from transducer 38 by a plurality of resonant bending wave modes in an area extending transversely of the thickness of the panel 18,19, wherein the frequencies of the resonant bending wave modes are interleaved in a predetermined frequency range so that resonant bending wave modes are substantially evenly distributed in frequency, and wherein the transducer 38 is mounted at a location on the panel 18,19 for coupling to the resonant bending wave modes so as to vibrate the panel 18,19 and excite the resonant bending wave modes in the panel 18,19, the resonant bending wave modes in turn producing an acoustic output.

[0029] In one embodiment, the display panel 18,19 comprises a rigid center portion sandwiched between two thin sheets. The center portion may be of a honeycomb or foam construction, and the thin sheets may be plastic, on the order of 1 mm or less. The panel may be supported around its periphery by a resilient material such as foam. The transducer is mounted within the center portion so as to contact and vibrate one of the thin sheets.

[0030] Techniques for generating driving signals for the transducer 38 are known, and further information may be obtained from New Transducers Limited, from the Internet, and from the above-identified patents. The patents by New Transducers Limited, identified above, teach shapes, stiffnesses, and other aspects of the transducer and resonator that are applicable to the present invention.

[0031] Accordingly, a display panel in a slot machine is transformed into a resonant mode panel by affixing a transducer to the back of the display panel and supplying suitable signals to the coil of the transducer. The display panel 18,19 may have any type of printing thereon. Various audio effects are achievable that could not be achieved with conventional speakers.

[0032] Alternatively, a more conventional sound transducer may have its moveable coil affixed to the back of the display panel and its magnet assembly affixed to the housing of the slot machine. The transducer is supplied with conventional analog signals to vibrate at the audio frequencies to be reproduced to simply vibrate the display panel 18,19 as a conventional diaphragm of a speaker. However, the resonant mode of operation is preferred in this particular use.

[0033] While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as fall within the true spirit and scope of this invention. 

What is claimed is:
 1. A gaming machine comprising: at least one display panel in the gaming machine, a front surface of the display panel having printed on it information for a player; and at least one transducer mounted to a back surface of at least one display panel so as to impart vibration to the display panel and create an acoustic signal audible to the player.
 2. The machine of claim 1 further comprising: an amplifier coupled to the transducer for applying excitation signals to the transducer to cause the transducer to vibrate, wherein the at least one display panel sustains and propagates input vibrational energy from the transducer by a plurality of resonant bending wave modes in an area extending transversely of a thickness of the at least one display panel, wherein frequencies of the resonant bending wave modes are interleaved in a predetermined frequency range so that resonant bending wave modes are substantially evenly distributed in frequency, and wherein the transducer is mounted at a location on the at least one display panel for coupling to the resonant bending wave modes so as to vibrate the at least one display panel and excite the resonant bending wave modes in the at least one display panel, the resonant bending wave modes in turn producing an acoustic output.
 3. The machine of claim 1 wherein the at least one transducer and the at least one display panel form a distributed mode acoustic radiator, where sound is produced from vibration of the at least one display panel due to resonant bending wave modes.
 4. The machine of claim 1 wherein the at least one transducer comprises a magnet assembly and a wire coil assembly, wherein the magnet assembly is rigidly affixed to the at least one display panel, and wherein the coil assembly is resiliently affixed to the at least one display panel.
 5. The machine of claim 1 wherein the at least one transducer comprises a magnet assembly and a wire coil assembly, wherein the coil assembly is rigidly affixed to the at least one display panel, and wherein the magnet assembly is resiliently affixed to the at least one display panel.
 6. The machine of claim 1 further comprising a game display for displaying a game to the player.
 7. The machine of claim 6 wherein the game display comprises a video screen.
 8. The machine of claim 6 wherein the game display comprises motor driven reels.
 9. The machine of claim 1 wherein the at least one display panel is formed of plastic.
 10. The machine of claim 1 wherein the at least one display panel comprises one panel.
 11. The machine of claim 1 wherein the at least one display panel comprises two panels.
 12. The machine of claim 1 wherein there are multiple transducers mounted on a single display panel. 13 The machine of claim 1 wherein the at least one display panel has printed on it information regarding a game played on the gaming machine.
 14. The machine of claim 1 wherein the at least one display panel has printed on it pay tables for a game played on the gaming machine.
 15. A method of generating sound in a gaming machine, the machine having at least one display panel, a front surface of the display panel having printed on it information for a player, the method comprising: applying excitation signals to at least one transducer mounted to a back surface of the at least one display panel so as to impart vibration to the at least one display panel and create an acoustic signal audible to the player.
 16. The method of claim 15 wherein applying excitation signals comprises applying excitation signals to the transducer to cause the transducer to vibrate, wherein the at least one display panel sustains and propagates input vibrational energy from the transducer by a plurality of resonant bending wave modes in an area extending transversely of a thickness of the at least one display panel, wherein frequencies of the resonant bending wave modes are interleaved in a predetermined frequency range so that resonant bending wave modes are substantially evenly distributed in frequency, and wherein the transducer is mounted at a location on the at least one display panel for coupling to the resonant bending wave modes so as to vibrate the at least one display panel and excite the resonant bending wave modes in the at least one display panel, the resonant bending wave modes in turn producing an acoustic output.
 17. The method of claim 15 wherein the at least one transducer and the at least one display panel form a distributed mode acoustic radiator, where sound is produced from vibration of the at least one display panel due to resonant bending wave modes. 